Process and apparatus for the production of luminous signs in electric gas dischargetubes



June 11, 1935 LEBEDENKO m ,@4,5?7

PROCESS AND APPARATUS FOR THE PRODUCTION OF LUMINOUS SIGNS IN ELECTRIC GAS DISCHARGE TUBES A Filed Dec. 15, 1932 3 Sheets-Sheet 1 N/wm/ Azaezavm. RUDOLF 15v). Miro/slaw ZE/TL/N.

HTTOR/VEY N. LEBEDENKO ET AL 2,04,577

June 11, 1935.

PROCESS AND APPARATUS FOR THE PRODUCTION OF LUMINOUS SIGNS IN ELECTRIC GAS DISCHARGE TUBES Filed Dec. 15, 1952 :5 Sheets-Sheet 2 /N VE/V TOR S Nuwuw Lsesasmna- RuooLF LEW. Mano/31.0w 2E1 TL/N- HTTOR/VEY.

June 11, 1935. LEBEDENKQ r AL 2,604,577

PROCESS AND APPARATUS FOR THE PRODUCTION OF LUMINOUS SIGNS IN ELECTRIC GAS DISCHARGE TUBES Filed Dec. 15, 1952 3 Sheets-Sheet 3 MW 05 E m M: M 5 Mi Patented June 11, 1935 UNITED STATES PATENT OFFICE PROCESS AND APPARATUS FOR THE PRO- DUCTION F LUMINOUS SIGNS IN ELEC- TRIO GAS DISCHARGE TUBES Application December 15, 1932, Serial No. 647,426,.

. In Germany October 15, 1931 22 Claims.

This invention relates to a process and apparatus for producing luminous signs, drawings or designs in electric gas or vapour discharge tubes.

The production of luminous signs in electric gas or vapour discharge tubes by means of internal electrodes is already known. In such devices the cathode is in the form of a written character or the like and adapted to be covered with a glowing discharge when the electrodes are connected with a source of electric energy of high frequency. The production of luminous signs by suitably forming gas discharge tubes is also known.

It has also been proposed to provide electric gas discharge tubes with external electrodes and to induce the current capacitively through the walls of the tube. In such an arrangement it has hitherto been the practice to utilize the emission of light in a longitudinal direction within the tube and between the two external electrodes. The present invention is based on the known, but hitherto little regarded phenomenon, that a glowing discharge also appears when external electrodes are used and the present invention includes, further, the provision of external electrodes in the form of the signs or configuration desired to be produced.

By giving the external electrodes the suitable shape it is possible, as experiments have shown, to produce a discharge within the tube of a shape similar to the form of the electrodes. The pres- .sure of'the gas with which the tubes or containers are filled is such that opposite the point of contact of the external electrodes and within the container, a glowing discharge is produced having approximately the form of the external electrodes, electric bridges between the electrodes or groups of electrodes of different polarity being formed by an ionized gas space in the interior of the tube. The said ionized gas space may be luminous and may be of a difl'erent colour or of less intensity than the glowing discharge or it may be entirely invisible. For instance, an external electrode having the form of a letter produces a glowing discharge in the form of the said letter. In this way surfaces of any desired shape can be represented.

Another feature of the invention consists in external electrodes suitably arranged so as to be readily exchangeable. High frequency current is preferably employed for feeding.

The external electrodes are not under the direct influence of the gas discharge and they may be made, therefore, of any suitable conductive material which will not-corrode under the influence of I electric operations.

A further advantage of the present invention is the representation of luminous designs of superficial character in combination with the P0381! bility of their ready exchangeability. These features represent important technical and economical advantages.

In carrying out the invention it has been found particularly suitable to use containers having a rarifled gas space, such as Dewar tubes, of desired shape and to use a gas pressure suitable for them.

It has been found advantageous for the production of a glowing discharge in the form of the external electrodes to use a container in which the distance between the two opposite walls is relatively small, so that a flattened gas space is formed. By this arrangement a greatly improved visual efiect of the luminous signs is obtained.

The invention is based on the recognition of the fact that a gas discharge tube of a known type and of the configuration of a Dewar tube is particularly suitable for the desired purpose, as it has the requisite of a narrow and flattened gas space. Such tube is not difllcult to manufacture.

The optimum sharpness of the contour of the luminous eflfects or forms produced by the capacitive influence of the external electrodes upon the gas space, and the influencing as regards the spectrum and the intensity of the electric bridge formed between the electrodes or groups of electrodes of different polarity by an ionized gas space in the interior of the tube, which appears in adifierent colour, or of lesser intensity than the luminous forms or signs, or which is not luminous at all, can be eiifected by suitably adjusting the gas pressure. For instance for a neon-helium mixture with a distance between the walls of the tube of about mm. a gas pressure of between 55 and 70 mm. was found to be most suitable. For air the suitable gas pressure with the same distance between the walls was found to be about 35 to 40 mm. In general the most suitable gas pressure depends on the unobstructed length of path of the gas ions of the particular gas mixture.

Some illustrative forms of the invention are shown by way of example in the accompanying drawings, in which:--

Figure 1 illustrates the way in which a sign employing my novel electrodes, which may take any form, shape, or configuration, would appear to the eye of an observer.

Figure 2 illustrates an arrangement of the electrodes in combination with a Dewar tube.

Figure 3 shows an arrangement of electrodes in connection with a container of another construction.

Figure 4 discloses an arrangement of the electrodes within a sample tube.

Figure 5 illustrates an arrangement of electrodes in combination with a tube having open ends.

Figure 6 showsan arrangement in which external liquid electrodes are employed.

Figure 7 is a vertical sectional view taken on the line 'I-lof Figure 6,. the tube being shown in elevation.

Figure 8 is a horizontal sectional view taken on the line H of Figure 6.

In Figures 1 and 2 of the drawings, 2 indicates a tube, for instance a simple tube or container made up of an inner and outer wall defining a cell which may or may not confine a gas in accordance with the teachings of our invention as hereinafter defined, exteriorly of the inner wall of the tubes are letter-shaped external electrodes 5-" are mounted. The electrodes conveniently fed for instance from a Tesla transformer, to one terminal of which they are connected, while the other terminal of the transformer, not shown, is connectedto an arrangement in a manner as hereinafter described. Opposite the external electrodes 5-! and within the tube 2 there are formed, as will be seen from Figures 1 and 2, glowing discharges 3-4 and I5- 20 of approximately the same shape as the electrodes.

Figure 2 shows an arrangement wherein the tube of Figure 1 is provided with the external electrodes 56-1--8-9l0 which are of different shape than those of Figure l and are mounted on a nonconductive support II, as for instance an easily removable tube of cardboard or suitable material. The external electrodes are connected in a suitable manner with one terminal l2 of a source of high frequency current. At It, there is illustrated an internal electrode which is connected to the other terminal I 4 of the source of current. This electrode is; preferably made of a net of conductive material, metallic gauze or the like, or of a translucent, reflective and conductive coating on the inside of the tube. We may form the translucent reflective and conductive coating 32 by (a) cathode diffusion; (b) by spraying a metal coating against the glass container through a movable screen between the spray nozzle and glass container; and (c) by a chemical method (by chemical reduction of the respective metal (silver, copper) from its solutions, the coating is very thin so that light rays will be visible therethrough. The external electrodes produce within the tube the luminous effects l5-l6|'| l8-i92ll which are of the same shape as the external electrodes and which may be observed through the internal electrodes by virtue of the light rays emanating from the zone of luminosity through the interstices in the metallic gauze or, if the electrodes be of a translucent variety the light rays penetrating the coating. The electrodes maybe reflecting, for instance being highly polished, which greatly enhances the visual effect of the luminous indicia and they may be partly, or entirely, covered with pigments provided with fluorescent admixtures or the like. The electrodes may be made from metal foil, sheet zinc, or may be applied as a conductive composition of matter as for instance metal powder, graphite, or the like,

Figure 5 shows an arrangement in which both the electrodes representing the signs are capacitive external electrodes. As compared with the previous arrangements this arrangement has the advantage that the tube which serves for the production of the light has no conductive internal parts so that, for instance, only the tube body, which is usually made of glass, has to be evacuated, which simplifies the process of production of such tube. In this arrangement there is no gas absorption of current-conducting metallic parts present and consequently the tube has a practically unlimited life, and more space for gas or vapor fillings is available.

In the example shown in Figure 3, the tube consists of coaxial cylinders having the inner walls 2! and 22 andthe common outer wall 23.

The space 24 between the radial walls 24' of the inner walls allows a more favourable distribution of the stresses in the glass. The external electrodes 25, 26, 21, 28, 28, 30 which are made in the form of signs are connected with the terminal, of a source of current. On the outer surface of the tube and opposite the sign elec-' trodes there is a mesh-like electrode 32 of the type hereinbefore described which is connected to the terminal 33 of a source of electric energy.

This electrode may be a net of conductive material or a translucent and reflecting conductive coating. The electrodes produce in the interior of the tube corresponding luminous forms 34, 35, 36, 31, 38, 39

Figure 4 shows a further embodiment of the invention, in which the external electrodes or groups of electrodes which produce the signs and which have a capacitive action are connected to different terminals of the source of current. In this arrangement the electrodes are preferably mounted on the same side of the outer surface of the tube. This construction is an improvement over those previously described in so far as all the electrodes are main electrodes. There is a considerably better utilization of the energy, and

furthermore, by means of the position of the electrodes on the same side of the outer surface of the tube, any loss of light is avoided, as distinguished from the arrangements according to Figures 2 and 5 wherein the position of the net r like electrode in'front of the tube sometimes tends to shade the electrodes 8, 9 and I0.

At 40 there is indicated a simple tube with inwardly bent end portions. The external electrodes 4| and42 are in the form of desired indicia, which are connected to the terminals 43, 44 of a source of current, as for instance a Tesla transformer. The electrodes produce the corresponding glowing forms or indicia 45 and 46 in the tube 40. The ionized gas space 41 forms the electric bridge between the electrodes gas space 41 will emit a blue light.

Figure 5 shows the same principle applied to a double wall tube 48 formed as a hollow cylinder so that the electrode carrier 49 can be introduced from either end. The tube is suitably provided with enlarged portions as shown at 50, 5|, 52, 53 adapted to compensate for the thermal expansion of the material of the tube. The external electrodes are indicated at 54 to 6! inclusive and are connected to the terminals 62 and 63 of a source of current, in the manner shown in this figure. The electrodes produce the luminous indicia 64 to H. Between the electrodes of different polarity are the ionized gas spaces 12, 13, I4, I5, l6, II. The most suitable mode of connection of the electrodes depends in each case upon the number, size and arrangement of the signs to be represented.

The electrode carrier 49 may be of elastic material and in the form of a rubber balloon which, after insertion into the cavity of the tube 48, is inflated and which may be deflated before removal from the tube. This arrangement prevents any damage to the tube wall which might occur when a rigid electrode carrier is inserted or withdrawn and furthermore a more reliable and intimate connection between the external electrodes and the wall of the tube is assured. By using an electrode carrier of suitable construction adapted to move with respect to the discharge tube, an advancing appearance of the characters can be obtained, as the luminous sign travels along with the electrodes.

Figure 6, finally, shows a form of the invention in which at least one electrode is a fluid. There is illustrated a Dewar tube I8 closed at one end, on the wall of which are mounted the external electrodes 80, 8|, 82, 83 formed into suitable indicia and which are conductively connected with the terminal 19 of a source of high frequency current. The other electrode is the liquid 84. This liquid may be water or the like which may be quiescent or may flow from a source of supply over the external surface of the tube into the container 85 from where it is discharged through an outlet 86. The water supply pipe 8'! is conductively connected with the other terminal 88 of the source of current. While the electrodes 80, BI, 82, 83 produce the corresponding glowing designs 89, 90, 9|, 92 the liquid electrode 93 which builds up on the surface of the tube 18 produces in the gas space of the tube a glowing discharge 94 of a form corresponding to the shape of the liquid stream. The liquid may travel, and the glowing discharge 94 moves with'it, so that, by looking through the liquid, the observer has the impression of seeing a fiowing light. The electric bridge is formed at 95, 96, between the electrodes of desired configurations and the flowing light. The liquid electrode 84 can also be provided with fluorescent or phosphorescent admixtures, which further enhance the effect. The procedure may also be such that the liquid which constitutes one electrode is passed with or without entrapped air through liquid conveying means, for instance through a rubber hose which may be wound several times along the inner external surface of the tube, in such a manner, that the liquid and its conveying means remain invisible, and only the corresponding glowing effects which travel along with the liquid become visible in the tube. The supply transformer can be constructively connected with the apparatus by arranging the same within the socket of a support adapted to carry the tube.

It will be apparent from the foregoing description that various changes in the details of the constructions described herein may be made without departing from the inventive concept. The changes will readily suggest themselves to those skilled in the art and it will be accordingly understood that it is intended and desired to embrace within the scope of this invention such modifications and changes as may be necessary to adapt it to varying conditions and uses.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States, is:

1. In a luminous discharge tube for operation from high frequency currents, an envelope of dielectric material enclosing an ionizable gas, a support removably connectible with said enve-- lope, and a multiplicity of electrodes mounted on said support in positions capacitatively related to the ionizable gas in said envelope.

2. In a luminous discharge tube for operation from high frequency currents, an envelopeof dielectric material enclosing an ionizable gas, a non-conductive support removably connectible with said envelope, and a multiplicity of electrodes mounted on said non conductive support in positions capacitatively related to the ionizable gas in said envelope. 4

3. In a luminous discharge tube for operation from high frequency currents, an envelope of dielectric material enclosing anionizable gas, a tubular support removably connectible with said envelope, and a multiplicity of electrodes mounted on said tubular support in positions capacitatively related to the ionizable gasin said envelope.

4. A luminous discharge tube for operation from high frequency currents comprising an envelope of dielectric material enclosing-an ionizable gas, a removabletubular support of insulation material disposed adjacent said envelope, and a multiplicity of electrodes mounted on said removable tubular support in positions capacitatively related to the ionizable gas in said envelope.

5. A luminous discharge tube comprising an envelope confining a body of ionizable gas, a support disposed adjacent said envelope, and a plurality of electrodes of opposite polarity mounted in alternate order on said support in capacitative relation to the body of ionizable gas in said envelope, said electrodes having configurations of a pattern in which selected ionization of a por-, tion of the ionizable gas in said envelope may be effected when said electrodes are charged with high frequency energy.

6. An apparatus of the character described comprising, in combination, a tube, the walls of which define a gas space therebetween, an ionizable gas in said gas space, anon-conductive supporting means adjacent the walls of said tube, an

indicium shaped electrode mounted on said non-,.

conductive supporting means within the tube and I lucent electrode opposite the indicium shaped electrode, the electrodes constituting terminals for connection to" a high frequency source for ionizing the gas within the gas space for producing a glow discharge within the tube of a configuration similar to that of the indicium shaped electrode.

'7. An apparatus of the character described comprising, in combination, a tube, the walls of which define a gas space therebetween, an ionizable gas within the gas space, supporting means adjacent the walls of said tube, indicia shaped electrodes mounted on said supporting means within the tube and disposed exteriorly of the gas space, and a translucent electrode opposite the indicia shaped electrodes and exterior of the gas space and outside of the tube, the electrodes constituting terminals for connection to a high frequency source for ionizing the gas within the gas space for producing a glow discharge within the tube and or a conflsuration similar tothe configuration oi the indicia shaped electrodes upon energization thereof.

8. An apparatus of the character described comprising, in combination, a tube-having'a cell containing a rarified gas, indicia shaped electrodes, a fluid receptacle enclosing said cell, a fiuid in said receptacle forming an electrode opposite the indicia shaped electrodes, means for supporting the indicia shaped electrodes exteriorly oi the cell of the tube, and means connecting the electrodes with a source of electric energy.

9. An: apparatus of the character described comprising, in combination, a vacuum tube, the.

walls of which define a vacuum space therebetween containing a gas at a suitable reduced pressure, a support formed from insulation material disposed adjacent the exterior wall or the tube, indicia shaped electrodes carried by said support, and means connecting the electrodes with a source of electric energy, whereby the indicia shaped electrodes form portions of a glow discharge path within the vacuum space of the tube together with an electric bridge of ionized gas between electrodes of difierent polarity upon energize.- tion thereof.

10. An apparatus of the: character described .comprising, in combination, a vacuum tube, the walls of which define a flattened vacuum space therebetween, an electrode carrier mounted: adjacent one of the walls of said vacuum tube, capacitive interconnected external indicia shaped electrodes or difierent polarity supported by said carrier adjacent the walls defining the vacuum space and arranged on opposite sides thereof, and means connecting the said electrodes with a source of energy.

11. An apparatus of the character described comprising, in combination, a flattened vacuum tube, the walls or which define a vacuum space therebetween, an electrode carrier disposed adjacent one of said walls, capacitively spaced electrodes of diilerent polarity insulatingly supported on said electrode carrier and exterior of the vacuum space, and means connecting the electrodes with a source of energy, whereby a glow discharge of a configuration corresponding to the configurations of the electrodes is produced through the vacuum space in said tube.

12. An apparatus of 'the character described comprising, in combination, an envelope, the walls of which define a gas space therebetween containing a plurality of gases at a suitable reduced pressure, supporting means adjacent the walls of said envelope, indicia shaped electrodes carried by said supporting means adjacent one wall of said envelope, a translucent electrode exterior to the other wall of said envelope, and ineans connecting the electrodes with a source of energy, the said electrodes being spaced from each other to provide an ionizing path through the gas space to produce upon their energization a glow discharge within the gas space and of a similar configuration as the configurations of the indicia shaped electrodes together with an electric bridge between electrodes of different polarity.

13. An apparatus of the character described comprising, in combination, a tube, the walls of which define a vacuum space therebetween, an ionizable gas confined by said walls, a non-conductive removable supporting structure positioned adjacent said walls, indicia electrodes carried by said supporting structure adjacent the walls and disposed exteriorlyof the vacuum space and conducting leads connected with the indicia electrodes, said leads being connectible to a high frequency source.

14. An apparatus of the character described comprising, in combination, a vacuum tube, the walls of which define a vacuum space therebetween, an ionizable gas confined by said walls, a removable supporting structure positioned adjacent said walls, movable indicia shaped electrodes mounted on said supporting structure within the tube and disposed exteriorly oi. the vacuum space, a translucent electrode opposite the indicia shaped electrodes, and conducting leads connected with said electrodes and connectible with a high frequency source whereby a glow discharge is produced within the tube of a configuration similar to the configurations oi the indicia shaped electrodes.

15. An apparatus of the character described comprising, incombination, a vacuum tube, the walls of which define a vacuum space therebetween, an ionizable gas confined by said walls, indicia shaped electrodes within the tube and disposed exteriorly of the vacuum space, a removable electrode carrier 01' a tube like configuration for the said indicia shaped electrodes, a translucent electrode opposite the indicia shaped electrodes and exterior of the vacuum space and outside of the vacuum tube, and conducting leads connected with said electrodes and connectible with a high frequency source whereby a glow discharge is produced within the tube of a configuration similar to the configurations of the indicia shaped electrodes.

16. An apparatus of the character described comprising, in combination, a vacuum tube, the walls of which define a gas space therebetween, an ionizable gas confined in said gas space, supporting means adjacent the walls of said tube, reflecting indicia shaped electrodes carried by said supporting means within the tube and disposed exteriorly of the gas space, and an electrode admitting of the passage of light rays therethrough and opposite the indicia shaped electrodes, the electrodes forming terminals for impressing ionizing potential across the gas space for producing a glow discharge, within the tube of a configuration similar to the configurations of the indicia shaped electrodes.

17. An apparatus of the character described comprising, in combination, a tube consisting-oi an inner and outer wall defining a gas space therebetween containing a plurality' of gases, supporting means adjacent said tube, indicia shaped electrodes mounted on said supporting means adjacent the inner wall of the tube and exterior of the gas space thereof, a container surrounding the exterior wall of the tube and spaced therefrom, and a flowing translucent electrode between the exterior wall of the tube and the container capacitively interconnected with the indicia shaped electrodes and forming an ionizing path through the gas space to produce a glow discharge within the gas space of a configuration similar to the configurations of the indicia electrodes together with an electric bridge between the indicia shaped electrodes and the 'fiowing translucent electrode.

18. An apparatus of I the character described comprising, in combination, an envelope consistmg of an inner and an outer wall defining a flatof the envelope and exterior of the gas space thereof, a container surrounding the exterior wall of the envelope and suitably spaced therefrom, a liquid electrode within the container and contacting with the exterior wall of the envelope, and means connecting the indicia and liquid electrodes with a source of electric energy, the liquid electrode being capacitively interconnected with the indicia electrodes upon energization of the electrodes forming an ionized path through the gas space of the envelope opposite the indicia electrodes for producing a glow discharge together with an illumination of the gas space in areas between the liquid and indicia electrodes of different color than the color of the glow discharge.

19. An apparatus of the character described comprising, in combination, an envelope the walls of which define a gas space therebetween, an ionizable gas in said gas space, a support adjacent said envelope, electrodes carried by said support adjacent the envelope and spaced at suitable locations along the surface thereof and disposed externally of the gas space, a container for said envelope, a flowing fluid directed into said container, and substantially surrounding the said envelope but maintained out of contact with the aforesaid electrodes, and means for connecting the fluid in said container and electrodes with a source of energy, the said electrodes being disposed at such distance with respect to the flowing fluid as to enable a discharge to pass between the said electrodes and said flowing fluid through the interior of the envelope for ionizing the gas therein to produce a flowing glow discharge within the envelope along the portion of the envelope immersed in the said fluid, the said glow discharge fiowing through the envelope incident to the flow of fluid.

20. An apparatus of the character described, comprising, in combination, an envelope having spaced surfaces defining a gas space containing a gas to be illuminated in selected zones upon ionization in said zones, a support adjacent said envelope, an indicium shaped electrode mounted on said support and disposed adjacent a surface of the envelope and exterior of the gas space, and a second electrode carried by said support and spaced from said first named electrode and lying adjacent a surface of the envelope whereby, when said electrodes are energized a discharge is created between the electrodesand through the gas to i'onize the gas and illuminate the gas in the zone between the electrodes, said illuminated zone taking the shape of the indicium shaped electrode, said envelope having a shape in the direction of its length other than that of the indicium electrode.

21. An apparatus of the character described comprising, in combination, a tube the walls of which define a gas space, supporting means adjacent said tube, an indicium shaped electrode carried by said supporting means within the tube and disposed exteriorly of the gas space, and a second electrode opposite the indicium shaped electrode, said electrodes forming terminals for impressing an ionizing potential upon the gas space of the tube for producing a glow discharge of a configuration corresponding to the form of the indicium shaped electrode, said glow discharge being visible through said second electrode.

22. An apparatus of the character described comprising, in combination, a tube the walls of which enclose an ionizable gas space, a support adjacent said tube, an indicium shaped electrode carried by said support within the tube and disposed exteriorly of the gas space, and a second electrode opposite the indicium shaped electrode, said electrodes constituting terminals for impressing an ionizing potential upon the gas space within the tube for producing a glow discharge of a configuration corresponding to form of the indicium shaped electrode, said second electrode admitting of the passage of light rays therethrough whereby said glow discharge is visible to the eye.

NIKOLAI LEBEDENKO. RUDOLF LEVY. WLADISLAW ZEITLIN. 

